The trend in modern distribution systems is towards having large distribution depots located on the outskirts of towns and cities near main trunk roads. These large distribution depots have a number of significant logistical advantages for the operators in terms of stock control and speed and ease of distribution of goods. However, depots have become larger with many having dozens or even hundreds of trailers on site and allocated a job at any one time. In particular for larger companies, it has become difficult to track the trailer use in the depot due to the sheer number of trailers and due to the use of standardized trailers having identical appearance.
Furthermore, trailers for many goods are loaded and then moved from a known loading bay to a parking area to await a tractor or prime mover to take it to its destination. Trailers used in this environment will be assigned a trailer number or identifier. To reduce the risk that a driver takes the wrong trailer, there is usually an independent manual check at the exit gate that the driver has taken the correct trailer.
Patent document WO 2005/115811 discusses an anti-theft system for a trailer comprising an immobiliser which is adapted to communicate with an identified mobile telephone.
This system has given rise to significant logistical efficiencies but is still prone to human error and has a high degree of manual input. This slows down the operation of the trailer depot and results in additional costs for operators due to the inefficient use of resources.